Dynamically extending loudspeaker capabilities

ABSTRACT

The present disclosure provides systems and methods to dynamically extend loudspeaker capabilities. In particular, a system comprising a loudspeaker can receive an electronic audio signal. Responsive to a change in available headroom, one or more parameters of an equalizer being applied to at least a portion of the signal in order to extend a physical low-frequency response of the loudspeaker can be modified based on the change in available headroom. Additionally or alternatively, responsive to the change in available headroom, a bandwidth of low-frequency content of the signal that is being synthesized by the system to extend low-frequency capability of the system beyond physical capabilities of the system can be adjusted based on the change in available headroom.

PRIORITY CLAIM

This application claims priority to U.S. Patent Application Ser. No.62/567,710, filed Oct. 3, 2017, and entitled “DYNAMICALLY EXTENDINGLOUDSPEAKER CAPABILITIES,” the disclosure of which is incorporated byreference herein in its entirety.

FIELD

The present disclosure relates generally to audio. More particularly,the present disclosure relates to dynamically extending loudspeakercapabilities.

BACKGROUND

A loudspeaker or speaker is an electroacoustic transducer that convertsan electronic audio signal into a corresponding sound. For example, aloudspeaker can include a magnet and a voice coil, which can be attachedto a diaphragm. When an electronic signal is applied to the voice coil,a magnetic field can be created by the electric current in the voicecoil, making it a variable electromagnet, which can interact with thefield of the magnet to generate mechanical force that causes the voicecoil and thus the attached diaphragm to move and produce audiofrequencies under the control of the applied signal.

SUMMARY

Aspects and advantages of embodiments of the present disclosure will beset forth in part in the following description, or can be learned fromthe description, or can be learned through practice of the embodiments.

One example aspect of the present disclosure is directed to a method fordynamic equalization. The method can include receiving, by a systemcomprising a loudspeaker, an electronic audio signal. The method caninclude, responsive to a change in available headroom, modifying, basedon the change in available headroom, one or more parameters of anequalizer being applied to at least a portion of the signal in order toextend a physical low-frequency response of the loudspeaker.

Another example aspect of the present disclosure is directed to a methodfor dynamically extending low-frequency capability of an audio system.The method can include, receiving, by a system comprising a loudspeaker,an electronic audio signal. The method can include, responsive to achange in available headroom, adjusting, based on the change inavailable headroom, a bandwidth of low-frequency content of the signalthat is being synthesized by the system to extend low-frequencycapability of the system beyond physical capabilities of the system.

Another example aspect of the present disclosure is directed to a systemfor dynamically extending loudspeaker capabilities. The system caninclude a loudspeaker and circuitry. The circuitry can be configured tocause the system to, responsive to a change in available headroom:modify, based on the change in available headroom, one or moreparameters of an equalizer being applied to at least a portion of asignal in order to extend a physical low-frequency response of theloudspeaker; and adjust, based on at least one parameter of the one ormore parameters, a bandwidth of low-frequency content of the signal thatis being synthesized by the system to extend low-frequency capability ofthe system beyond physical capabilities of the system.

Other aspects of the present disclosure are directed to various systems,apparatuses, non-transitory computer-readable media, and electronicdevices.

These and other features, aspects, and advantages of various embodimentsof the present disclosure will become better understood with referenceto the following description and appended claims. The accompanyingdrawings, which are incorporated in and constitute a part of thisspecification, illustrate example embodiments of the present disclosureand, together with the description, serve to explain the relatedprinciples.

BRIEF DESCRIPTION OF THE DRAWINGS

Detailed discussion of embodiments directed to one of ordinary skill inthe art is set forth in the specification, which makes reference to theappended figures, in which:

FIG. 1 depicts a block diagram of an example system according to exampleembodiments of the present disclosure;

FIG. 2 depicts example formulas for determining parameters according toexample embodiments of the present disclosure;

FIG. 3 depicts an example data format for parameters according toexample embodiments of the present disclosure;

FIG. 4 depicts an example array of parameters according to exampleembodiments of the present disclosure; and

FIGS. 5 and 6 depict flow chart diagrams of example methods according toexample embodiments of the present disclosure.

DETAILED DESCRIPTION

Generally, the present disclosure is directed to methods and systems fordynamically extending loudspeaker capabilities. In particular, in anaudio system comprising a loudspeaker, the amount of available headroomcan vary (e.g., based on available amplifier headroom, a change involume of the system, excursion characteristics of a transducer of theloudspeaker, analysis of an electronic audio signal received by thesystem, and/or the like). By modifying, based on the change in availableheadroom, one or more parameters of one or more techniques applied toextend capabilities of the loudspeaker, the technique(s) can bedynamically adjusted to exploit the currently available capacity of thesystem, further extending the capabilities of the system.

In some embodiments, the technique(s) applied to extend capabilities ofthe system can include applying an equalizer to at least a portion of asignal received by the system in order to extend the physicallow-frequency response of the loudspeaker. In accordance with aspects ofthe disclosure, responsive to a change in available headroom, one ormore parameters of such an equalizer can be modified based on the changein available headroom. Accordingly, the system can dynamically adjustthe equalizer based on the current capabilities of the system. In someembodiments, the equalizer can be a second-order low-frequency shelvingequalizer.

In some embodiments, the technique(s) applied to extend capabilities ofthe system can include synthesizing a bandwidth of low-frequency contentof a signal received by the system to extend the low-frequencycapability of the system beyond physical capabilities of the system. Forexample, psychoacoustic principles provide that a human brain willsynthesize a fundamental frequency as if the fundamental frequencyphysically existed if the sensory system associated with the brain isexposed to a harmonic structure corresponding to the fundamentalfrequency. Accordingly, the low-frequency capability of a system can beextended by producing a harmonic structure corresponding to afundamental frequency that is beyond the physical capabilities of thesystem. In accordance with aspects of the disclosure, responsive to achange in available headroom, a bandwidth of low-frequency content of asignal that is being synthesized to extend low-frequency capability ofthe system beyond physical capabilities of the system can be adjustedbased on the change in available headroom. Accordingly, the system candynamically adjust the bandwidth that is being synthesized based on thecurrent capabilities of the system.

The systems and methods described herein can provide a number oftechnical effects and benefits. For example, the systems and methodsdescribed herein can extend the capabilities of a system comprising aloudspeaker based on the currently available capacity of the system.

With reference now to the Figures, example embodiments of the presentdisclosure will be discussed in further detail.

FIG. 1 depicts a block diagram of an example system according to exampleembodiments of the present disclosure. Referring to FIG. 1, system 100can include source 102, circuitry 104, amp (or amplifier) 112, andloudspeaker 114. Source 102 can produce an electronic audio signal andtransmit the signal to circuitry 104. Circuitry 104 can receive thesignal from source 102 and can be configured to modify the signal (e.g.,via digital signal processing) and then transmit the modified signal toamp 112. Amp 112 can receive the modified signal from circuitry 104,amplify the signal, and transmit the amplified signal to loudspeaker114, which can produce audio frequencies in accordance with theamplified signal. Circuitry 104 can comprise one or more processors 106and memory 108. Memory 108 can store instructions 110, which whenexecuted by processor(s) 106 can cause circuitry 104 (and thus system100) to perform one or more functions described herein. It will beappreciated that in some embodiments, circuitry 104 can comprise source102.

Circuitry 104 can be configured to modify the signal received fromsource 102 in accordance with one or more techniques for extending thecapabilities of loudspeaker 114 (and thus system 100). For example,circuitry 104 can be configured to apply an equalizer to at least aportion of the signal received from source 102 in order to extend aphysical low-frequency response of loudspeaker 114. In some embodiments,the equalizer can be a second-order low-frequency shelving equalizer. Inaccordance with aspects of the disclosure, circuitry 104 can beconfigured to, responsive to a change in available headroom (e.g., basedon available headroom of amp 112, a change in volume of system 100,excursion characteristics of a transducer of loudspeaker 114, analysisof the signal received from source 102, and/or the like), modify one ormore parameters of the equalizer based on the change in availableheadroom. Accordingly, system 100 can dynamically adjust the equalizerbased on the current capabilities of system 100.

In some embodiments, the equalizer can be configured to apply a Linkwitztransform to the portion of the signal. In such embodiments, theparameter(s) modified can include a gain for the Linkwitz transformand/or a frequency for the Linkwitz transform.

FIG. 2 depicts example formulas for determining parameters according toexample embodiments of the present disclosure. Referring to FIG. 2,formula 202 illustrates an example approach for determining the gain forthe Linkwitz transform. As illustrated, the gain for the Linkwitztransform can be determined by determining the negative of the volume ofsystem 100 (e.g., in decibels) less the make-up gain of system 100(e.g., the make-up gain of the backend audio limiter gain stage indecibels), and then taking the minimum of the result and a fixed limit(e.g., 18 decibels).

Formula 204 illustrates an example approach for determining alow-frequency cutoff. As illustrated, the low-frequency cutoff can bedetermined by dividing the box-tuning frequency of system 100 before theLinkwitz transform is applied to the at least a portion of the signal(e.g., determined based on empirical evidence) by the result of two tothe power of the result of dividing the gain for the Linkwitz transformby twelve (e.g., for each decibel of volume attenuation, the frequencycan be reduced by one-twelfth of an octave).

Formula 206 illustrates an example approach for determining thefrequency for the Linkwitz transform. As illustrated, the frequency forthe Linkwitz transform can be determined by taking the average of thelow-frequency cutoff and the box-tuning frequency of system 100 beforethe Linkwitz transform is applied to the at least a portion of thesignal.

In some embodiments, circuitry 104 can be configured to synthesize abandwidth of low-frequency content of the signal received from source102 to extend the low-frequency capability of system 100 beyond thephysical capabilities of system 100. For example, circuitry 104 can beconfigured to cause system 100 to produce (e.g., via loudspeaker 114) aharmonic structure corresponding to a portion of the content of thesignal comprising a fundamental frequency that is beyond the physicalcapabilities of system 100 such that a human brain synthesizes thefundamental frequency as if the fundamental frequency physicallyexisted. In accordance with aspects of the disclosure, circuitry 104 canbe configured to, responsive to a change in available headroom (e.g.,based on available headroom of amp 112, a change in volume of system100, excursion characteristics of a transducer of loudspeaker 114,analysis of the signal received from source 102, and/or the like),adjust the bandwidth of the content being synthesized based on thechange in available headroom. Accordingly, system 100 can dynamicallyadjust the bandwidth that is being synthesized based on the currentcapabilities of system 100.

Referring to FIG. 2, formula 208 illustrates an example approach fordetermining the frequency for the bandwidth of the low-frequencycontent. As illustrated, the frequency may be determined by multiplyingthe low-frequency cutoff by a constant (e.g., a device specific value(e.g., 0.94) determined to retain a relationship between the twofrequencies).

In some embodiments, circuitry 104 can be configured to apply ahigh-frequency gain equalizer to at least a portion of the signalreceived from source 102 (e.g., in order to compensate for implementingthe technique(s) described above). Referring to FIG. 2, formula 210illustrates an example approach for determining the high-frequency gainfor such an equalizer. As illustrated, the high-frequency gain can bedetermined by multiplying the gain for the Linkwitz transform by aconstant (e.g., a device specific value (e.g., 0.39) determined tocontrol loudness compensation).

FIG. 3 depicts an example data format for parameters according toexample embodiments of the present disclosure. Referring to FIG. 3,“speaker_cutoff_hz” can correspond to the box-tuning frequency of system100 before the Linkwitz transform is applied to the at least a portionof the signal, “lf_content_coeff” can correspond to the constant bywhich the low-frequency cutoff is multiplied to determine the frequencyfor the bandwidth of the low-frequency content, “maximum_gain_db” cancorrespond to the fixed limit utilized in determining the gain for theLinkwitz transform, “gain_scale_factor” can correspond to the product ofthe gain for the Linkwitz transform and the constant by which thelow-frequency cutoff is multiplied to determine the frequency for thebandwidth of the low-frequency content, “makeup_gain_db” can correspondto the make-up gain of system 100 utilized in determining the gain forthe Linkwitz transform, “high_shelf_hz” can correspond to a cutofffrequency for the high-frequency gain equalizer, and“high_shelf_gain_factor” can correspond to the constant by which thegain factor for the Linkwitz transform is multiplied to determine thehigh-frequency gain.

FIG. 4 depicts an example array of parameters according to exampleembodiments of the present disclosure. Referring to FIG. 4, an arraysimilar to that illustrated can be utilized to pass the parameter(s)described above to a digital signal processor configured to implementthe technique(s) described above.

FIGS. 5 and 6 depict flow chart diagrams of example methods according toexample embodiments of the present disclosure. Referring to FIG. 5, at(502), a system comprising a loudspeaker can receive an electronic audiosignal. For example, system 100 can receive a signal from source 102. At(504), there can be a change in available headroom. For example, therecan be a change in available headroom (e.g., based on available headroomof amp 112, a change in volume of system 100, excursion characteristicsof a transducer of loudspeaker 114, analysis of the signal received fromsource 102, and/or the like). At (506), responsive to the change inavailable headroom, one or more parameters of an equalizer being appliedto at least a portion of the signal in order to extend a physicallow-frequency response of the loudspeaker can be modified based on thechange in available headroom. For example, in some embodiments, theequalizer can be configured to apply a Linkwitz transform to the atleast a portion of the signal, and the parameter(s) can comprise a gainfor the Linkwitz transform and/or a frequency for the Linkwitztransform.

Referring to FIG. 6, at (602), a system comprising a loudspeaker canreceive an electronic audio signal. For example, system 100 can receivea signal from source 102. At (604), there can be a change in availableheadroom. For example, there can be a change in available headroom(e.g., based on available headroom of amp 112, a change in volume ofsystem 100, excursion characteristics of a transducer of loudspeaker114, analysis of the signal received from source 102, and/or the like).At (606), responsive to the change in available headroom, a bandwidth oflow-frequency content of the signal that is being synthesized by thesystem to extend low-frequency capability of the system beyond thephysical capabilities of the system can be adjusted based on the changein available headroom. For example, in some embodiments, system 100 canbe configured to produce (e.g., via loudspeaker 114) a harmonicstructure corresponding to a portion of the content of the signalcomprising a fundamental frequency that is beyond the physicalcapabilities of system 100 such that a human brain synthesizes thefundamental frequency as if the fundamental frequency physicallyexisted. In such embodiments, system 100 can be configured to adjust thebandwidth of the low-frequency content based on the change in availableheadroom (e.g., based on the low-frequency cutoff, which can be based onthe gain for the Linkwitz transform, which can be based on a change involume of system 100).

The technology discussed herein makes reference to servers, databases,software applications, and/or other computer-based systems, as well asactions taken and information sent to and/or from such systems. Theinherent flexibility of computer-based systems allows for a greatvariety of possible configurations, combinations, and/or divisions oftasks and/or functionality between and/or among components. Forinstance, processes discussed herein can be implemented using a singledevice or component and/or multiple devices or components working incombination. Databases and/or applications can be implemented on asingle system and/or distributed across multiple systems. Distributedcomponents can operate sequentially and/or in parallel.

Various connections between elements are discussed in the abovedescription. These connections are general and, unless specifiedotherwise, can be direct and/or indirect, wired and/or wireless. In thisrespect, the specification is not intended to be limiting.

The depicted and/or described steps are merely illustrative and can beomitted, combined, and/or performed in an order other than that depictedand/or described; the numbering of depicted steps is merely for ease ofreference and does not imply any particular ordering is necessary orpreferred.

The functions and/or steps described herein can be embodied incomputer-usable data and/or computer-executable instructions, executedby one or more computers and/or other devices to perform one or morefunctions described herein. Generally, such data and/or instructionsinclude routines, programs, objects, components, data structures, or thelike that perform particular tasks and/or implement particular datatypes when executed by one or more processors in a computer and/or otherdata-processing device. The computer-executable instructions can bestored on a computer-readable medium such as a hard disk, optical disk,removable storage media, solid-state memory, read-only memory (RAM), orthe like. As will be appreciated, the functionality of such instructionscan be combined and/or distributed as desired. In addition, thefunctionality can be embodied in whole or in part in firmware and/orhardware equivalents, such as integrated circuits, application-specificintegrated circuits (ASICs), field-programmable gate arrays (FPGAs), orthe like. Particular data structures can be used to more effectivelyimplement one or more aspects of the disclosure, and such datastructures are contemplated to be within the scope ofcomputer-executable instructions and/or computer-usable data describedherein.

Although not required, one of ordinary skill in the art will appreciatethat various aspects described herein can be embodied as a method,system, apparatus, and/or one or more computer-readable media storingcomputer-executable instructions. Accordingly, aspects can take the formof an entirely hardware embodiment, an entirely software embodiment, anentirely firmware embodiment, and/or an embodiment combining software,hardware, and/or firmware aspects in any combination.

As described herein, the various methods and acts can be operativeacross one or more computing devices and/or networks. The functionalitycan be distributed in any manner or can be located in a single computingdevice (e.g., server, client computer, user device, or the like).

Aspects of the disclosure have been described in terms of illustrativeembodiments thereof. Numerous other embodiments, modifications, and/orvariations within the scope and spirit of the appended claims can occurto persons of ordinary skill in the art from a review of thisdisclosure. For example, one or ordinary skill in the art can appreciatethat the steps depicted and/or described can be performed in other thanthe recited order and/or that one or more illustrated steps can beoptional and/or combined. Any and all features in the following claimscan be combined and/or rearranged in any way possible.

While the present subject matter has been described in detail withrespect to various specific example embodiments thereof, each example isprovided by way of explanation, not limitation of the disclosure. Thoseskilled in the art, upon attaining an understanding of the foregoing,can readily produce alterations to, variations of, and/or equivalents tosuch embodiments. Accordingly, the subject disclosure does not precludeinclusion of such modifications, variations, and/or additions to thepresent subject matter as would be readily apparent to one of ordinaryskill in the art. For instance, features illustrated and/or described aspart of one embodiment can be used with another embodiment to yield astill further embodiment. Thus, it is intended that the presentdisclosure cover such alterations, variations, and/or equivalents.

What is claimed is:
 1. A method for dynamic equalization, the methodcomprising: receiving, by a system comprising a loudspeaker, anelectronic audio signal; and responsive to a change in availableheadroom, modifying, based on the change in available headroom, one ormore parameters of an equalizer configured to apply a Linkwitz transformto at least a portion of the signal in order to extend a physicallow-frequency response of the loudspeaker, the one or more parameterscomprising a gain for the Linkwitz transform and a frequency for theLinkwitz transform.
 2. The method of claim 1, wherein the equalizercomprises a second-order low-frequency shelving equalizer.
 3. The methodof claim 1, comprising determining, based on a volume of the system anda make-up gain of the system, the gain for the Linkwitz transform. 4.The method of claim 1, comprising determining, based on a box-tuningfrequency of the system before the Linkwitz transform is applied to theat least a portion of the signal and a low-frequency cutoff, thefrequency for the Linkwitz transform.
 5. The method of claim 4,comprising determining, based on the box-tuning frequency of the systembefore the Linkwitz transform is applied to the at least a portion ofthe signal and the gain for the Linkwitz transform, the low-frequencycutoff.
 6. The method of claim 1, comprising, responsive to the changein available headroom, adjusting, based on at least one parameter of theone or more parameters, a bandwidth of low-frequency content of thesignal that is being synthesized by the system to extend low-frequencycapability of the system beyond physical capabilities of the system. 7.The method of claim 6, comprising producing, via the loudspeaker, aharmonic structure corresponding to a portion of the content of thesignal comprising a fundamental frequency that is beyond the physicalcapabilities of the system such that a human brain synthesizes thefundamental frequency as if the fundamental frequency physicallyexisted.
 8. The method of claim 6, wherein the at least one parametercomprises the gain for the Linkwitz transform.
 9. A method fordynamically extending low-frequency capability of an audio system, themethod comprising: receiving, by a system comprising a loudspeaker, anelectronic audio signal; and responsive to a change in availableheadroom: modifying, based on the change in available headroom, one ormore parameters of an equalizer configured to apply a Linkwitz transformto at least a portion of the signal in order to extend a physicallow-frequency response of the loudspeaker, the one or more parameterscomprising a gain for the Linkwitz transform and a frequency for theLinkwitz transform; and adjusting, based on the change in availableheadroom, a bandwidth of low-frequency content of the signal that isbeing synthesized by the system to extend low-frequency capability ofthe system beyond physical capabilities of the system.
 10. The method ofclaim 9, comprising producing, via the loudspeaker, a harmonic structurecorresponding to a portion of the content of the signal comprising afundamental frequency that is beyond the physical capabilities of thesystem such that a human brain synthesizes the fundamental frequency asif the fundamental frequency physically existed.
 11. The method of claim9, wherein adjusting the bandwidth comprises adjusting the bandwidthbased on the gain for the Linkwitz transform.
 12. The method of claim 9,comprising determining, based on a volume of the system and a make-upgain of the system, the gain for the Linkwitz transform.
 13. The methodof claim 9, comprising determining, based on a box-tuning frequency ofthe system before the Linkwitz transform is applied to the at least aportion of the signal and a low-frequency cutoff, the frequency for theLinkwitz transform.
 14. The method of claim 13, comprising determining,based on the box-tuning frequency of the system before the Linkwitztransform is applied to the at least a portion of the signal and thegain for the Linkwitz transform, the low-frequency cutoff.
 15. A systemcomprising: a loudspeaker; and circuitry configured to cause the systemto, responsive to a change in available headroom: modify, based on thechange in available headroom, one or more parameters of an equalizerconfigured to apply a Linkwitz transform to at least a portion of asignal in order to extend a physical low-frequency response of theloudspeaker, the one or more parameters comprising a gain for theLinkwitz transform and a frequency for the Linkwitz transform; andadjust, based on at least one parameter of the one or more parameters, abandwidth of low-frequency content of the signal that is beingsynthesized by the system to extend low-frequency capability of thesystem beyond physical capabilities of the system.
 16. The system ofclaim 15, wherein the circuitry is configured to cause the system toproduce, via the loudspeaker, a harmonic structure corresponding to aportion of the content of the signal comprising a fundamental frequencythat is beyond the physical capabilities of the system such that a humanbrain synthesizes the fundamental frequency as if the fundamentalfrequency physically existed.
 17. The system of claim 15, wherein theequalizer comprises a second-order low-frequency shelving equalizer. 18.The system of claim 15, wherein the at least one parameter comprises thegain for the Linkwitz transform.
 19. The system of claim 15, wherein thecircuitry is configured to cause the system to determine, based on avolume of the system and a make-up gain of the system, the gain for theLinkwitz transform.
 20. The system of claim 15, wherein the circuitry isconfigured to cause the system to determine, based on a box-tuningfrequency of the system before the Linkwitz transform is applied to theat least a portion of the signal and a low-frequency cutoff, thefrequency for the Linkwitz transform.